Mayor Julian Castro thanks his supporters and staff as results for the Pre-K 4 SA campaign come in during the election watch party at La Fonda on Main in San Antonio on Tuesday, Nov. 6, 2012. Standing with him are City Councilman Diego Bernal, from left, Castro's wife, Erica Castro and their daughter, Carina, Lila Cockrell and City Councilman Ray Lopez.

Photo By Jerry Lara/San Antonio Express-News

George Rodriguez, of the South Texas Alliance for Progress, talks with media as early voting results show an 87 vote lead for the City of San Antonio's Pre-K 4 SA initiatvie, Tuesday, Nov. 6, 2012.

While a majority of voters last week approved a local sales tax increase to fund an ambitious and comprehensive early education program, detailed voting and demographic data illustrate a city that was deeply divided on the measure.

Voters in far-North and Northeast Side precincts tended to cast ballots against the measure, while precincts inside Loop 410 almost entirely favored Pre-K 4 SA. Several precincts near the city's urban core and on the East Side also showed high levels of support.

A San Antonio Express-News analysis of precinct-level results, coupled with racial and income data from the U.S. Census Bureau, shows areas dominated by minorities tended to favor Pre-K 4 SA far more than areas dominated by Anglo voters.

The study also indicates a strong correlation between support for Pre-K and President Barack Obama, who won Bexar County but lost most of Texas.

Voters from low-, moderate-and middle-income areas were more likely to support the Pre-K initiative than were those from high-income areas.

Mayor Julián Castro, who staked his mayoral tenure on the success of the Pre-K initiative, acknowledged the differences.

“While I see a general pattern, I'm convinced that there was a good level of support across the city, even if that support didn't reach 50 percent in some precincts,” he said. “I think what the election showed is that when you do something right — build a broad coalition — that you can get broad-based support. And of course, folks will have preferences that show themselves by income and background, but that's diminishing.”

Portions of City Council District 9 — a Republican stronghold — favored the initiative, as well as precincts in District 8, which has historically swung between liberal and conservative council representation. District 10 is a predominantly conservative area as well.

Some political observers said they see a change in North Side voting habits based on the election totals for Pre-K, Obama and other Democrats.

While Republicans still hold the majority there, Democratic numbers are up.

In northern stretches of the city, opposition reached 60-plus percent — one North Side precinct opposed the measure by almost 73 percent — but in years past, that number would have been much higher, observers say.

In the North Side precincts, Pre-K was not entirely rejected by large margins. In a couple of precincts on the far Southeast Side, however, it was — by 77 percent to 83 percent of the vote.

Those precincts have a higher level of income than neighboring areas that supported the initiative.

In contrast, several inner-city precincts approved the measure by up to 83 percent, with more than 30 precincts supporting it at 75 percent or better.

Char Miller, a former Trinity University urban studies professor who's now director of the environmental analysis program at Pomona College in California, said a gulf remains between the perceptions of voters on the North Side vs. those on the South, West and East sides.

“I guess sadly, part of what we're seeing is the continual distinction between how Latino and black voters vote and how the largely white North Side votes on issues,” he said, “particularly with this one that could have been seen as a metropolitan whole — that the whole of the community believes that all of its children should have a strong pre-K educational experience.”

Of the 345 voting precincts that supported Pre-K 4 SA, 330 of them, or 95.7 percent, also supported Obama. And of the 155 precincts that opposed Pre-K 4 SA, 141, or 91 percent, also supported Mitt Romney for president.

Fifteen precincts that favored Romney included a majority of voters who supported Pre-K — a voting bloc targeted early on by the campaign, which hoped to woo independent and slightly right-leaning voters.

Miller said he expected to see a connection between Pre-K support and Obama's success in San Antonio.

“That would reinforce the larger arguments that are emerging in the wake of the 2012 election, that Republicans have missed a major opportunity to reach out to those who are not white, straight males,” he said.

On Thursday, Castro acknowledged that his appearance as keynote speaker at the 2012 Democratic National Convention and subsequent stumping for Obama likely hurt the Pre-K initiative in the minds of some Republican voters.

“It probably didn't help much with Republicans, but it did help with Democrats — and it didn't make a difference with independents,” he said. “Overall, most folks could separate the initiative from my role with the DNC.”

Still, Castro and the campaign targeted right-leaning voters early on.

Pre-K 4 SA isn't only about the intrinsic pursuit of better academics but a pragmatic approach to bolstering the city's workforce for the future, supporters have said.

If the program is successful, it will help anchor existing business in San Antonio and attract new, high-paying jobs to the city, they've said.

Miller said that approach sounds strong, but he questions its effectiveness.

“While they may believe that language is appropriate, and they see it as a rhetoric designed to cultivate the North Side, the North Side actually doesn't care to support the interest of the whole,” he said. “They're interested in their cul-de-sacs. And I think that's one of the dangers of a political environment that is cut off ... from the broader sweep of the community, and doesn't see a shared interest in bettering the lives of those who can, in fact, as the mayor said, boost the economic prosperity of the whole.”

But it's possible the campaign swayed enough North Side voters to push the measure over the finish line. In the early vote, Pre-K was ahead by only 87 votes. On Election Day, however, 25,641 more voters cast ballots in favor of Pre-K than against.

Castro credited a strong campaign and volunteer force in the final days of the campaign to push voters to the polls.

That effort included Castro and his twin brother, Joaquín, who was elected Tuesday to the 20th Congressional District. They stood with supporters on street corners holding signs encouraging people to vote for pre-k.

“It was a good volunteer force (on Election Day), knocking on doors, getting folks out to the polls, calling people — it added up,” Castro said. “It's always hard to tell how much, but it added up.”

Castro also took to Twitter, sending out a large number of tweets and retweets about voting and supporting the initiative. It was an attempt, he said, to engage younger voters.

Now that the initiative has passed, Castro and the City Council will begin to move toward implementation. The council is poised to adopt lease agreements next week for the first two model centers that will open for the 2013-14 school year.

They'll also appoint a board of directors, which will, in turn, hire an executive director to handle the program's day-to-day operations.

The sales tax increase, which brings the rate in San Antonio to 8.25 percent, will go into effect April 1.

“Folks from across the city made a great decision to invest in education today so that we can be more economically prosperous tomorrow,” Castro said “I am proud of the broad coalition behind the effort. It showed that in San Antonio, we're working well together to accomplish important things for our city.”